A passenger cabin of a vehicle may be heated via an engine when ambient temperatures are low. However, some hybrid vehicles may operate without activating the engine for a period of time to conserve hydrocarbon fuel. For such vehicles, it may be desirable to provide an alternative way of heating the passenger cabin. One way to heat a passenger cabin without starting an engine may be to supply heat to the passenger cabin via a heat pump. The heat pump extracts heat from ambient conditions to heat the passenger cabin. Heat pumps are effective at some temperatures, but their efficiency may degrade at lower temperatures. Therefore, it may be desirable to heat a vehicle's passenger cabin via a different device.
The inventor herein has recognized the above-mentioned disadvantages and has developed a method for heating a vehicle, comprising: increasing temperature of a coolant in a coolant loop that includes a heater core via supplying electrical current to a positive temperature coefficient (PTC) heater in response to ambient temperature being less than a threshold temperature; and increasing temperature of the coolant via heat transferred from a heat pump in response to ambient temperature being greater than the threshold temperature.
By heating coolant using a PTC heater and\or a heat pump, it may be possible to provide the technical result of heating a vehicle's passenger cabin over a wide range of ambient temperatures. Further, since coolant is heated by the PTC heater and the heat pump, many components of a non-hybrid vehicle may be used commonly with a hybrid vehicle or electric vehicle. For example, a ventilation system for a passenger cabin may be used commonly between hybrid and non-hybrid vehicles since coolant is the heat transfer medium in both types of vehicles. Additionally, an engine may be heated via the PTC heaters so that engine emissions and fuel consumption may be reduced.
The present description may provide several advantages. Specifically, the approach may improve passenger cabin heating of electric and hybrid vehicles. Further, the approach may reduce fuel consumption and vehicle emissions by warming an engine via a vehicle's kinetic energy. Further still, the approach may improve a vehicle's electric propulsion range by reducing charge consumed from a battery to heat a passenger cabin.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.